Thomas Fusillo, DO, MS

Avascular necrosis (AVN) is a progressive disease characterized by bone death secondary to an interruption of the relevant vascular supply. While it is most common in pediatrics and later adulthood, it can occur at any age. This case describes a previously healthy man in his mid-twenties who presented with worsening hip pain. Imaging, including X-ray and magnetic resonance, revealed severe marrow edema and early collapse of the femoral head. The patient was also found to have a severely elevated low-density lipoprotein level, leading to the diagnosis of AVN due to familial hyperlipidemia. He received a total hip arthroplasty and was started on high-intensity statin therapy. This case highlights the importance of considering AVN in the young adult population with hip pain as well as the appropriate workup and treatment.

Von Willebrand disease (VWD) is often thought of as a singular straight-forward pathology. However, VWD is a nuanced and complex disease consisting of six unique subtypes. The pathological basis for diagnosis revolves around both qualitative and quantitative testing of Von Willebrand factor (VWF). This is done via the ristocetin cofactor analysis, VWF antigen level, and VWF multimer level. The ratio of these values can then be used to further deduce the exact subtype of Von Willebrand disease. Alternative but more costly diagnostic tools include gene sequencing, thromboelastography, and platelet aggregometry. Proper diagnosis and differentiation of the various VWD subtypes is crucial if one is to achieve effective treatment. This is especially the case for type 1 versus 2B, where desmopressin is the treatment of choice for type 1 but can potentially worsen the disease course of type 2B due to its unique pathophysiology. Therefore, an intimate understanding of both pathophysiology and laboratory medicine is needed to make a diagnosis and create a treatment plan. While the management of VWD is generally reserved for a specialist, the primary care physician and hospitalist should be capable of ordering and even interpreting the appropriate tests in order to expedite the patient’s care.